I have an MKIV computer with a 4:3 screen. Everything works with the following exceptions: Split screen does not work quite as good as the 16:9 screen. With 16:9, you can get a map on the left side with cd track info on right. With the 4:3, as soon as you go to CD, it goes to full track info screen. You can however do splitscreen on navigation (map on left, directions on right)Also, it looks like you lose a sliver of the image on the right hand side with the 4:3 (i.e. satellite icon gets slightly cut off on the right side) Other than that, I have found it to work great, and definitely don't find the need to upgrade to a 16:9 screen.